But he says after a few months he started noticing emotional changes with his new girlfriend.

"It was certain behaviours that I think really started to make me think that there was something in her past that just wasn't quite right," he said.

"She would withdraw emotionally for no reason. She rarely ever smiled or was happy. Never expressed her feelings. She didn't like to be kissed. She was extremely controlling of her weight and her physical appearance."

Questioning prompted revelations of abuse

Problems in the relationship grew, and so too the questions.

"I was just driving along and I just rang her and I said 'I respect your right to not answer this question but I'm going to ask it anyway' and I just said 'were you sexually abused?'" he said.

"In that instant she just gasped and I took that opportunity and I said I'll take that as a yes and I think she just knew that the secret was out."

He says it was saddening to hear his worst fears confirmed.

"I don't remember judging her or getting upset and it just seemed that life was standing still," he said.

Mr Curtis says understanding his girlfriend's childhood explained some things, but it also had consequences for him and the relationship.

"I suppose the simplest way I can describe it is the victim blames the other partner for what has happened," he said.

"They really transfer blame and I would think without knowing it that this is what happens.

"They have such anger and resentment and hurt that has to come out some way and normally it's directed at the person close to them.

"It was, I suppose, demoralising. I felt so inadequate, both as a partner and as a man. I just felt useless."

Partners suffering second wave of trauma

Mr Curtis says there is a second wave of trauma being suffered by partners.

"If she was feeling sad it would affect my mood. If she was tense I'd end up feeling tense. Her moods probably set the mood between us," he said.

"It's an amazing but very sad dynamic."

Mr Curtis says he persuaded his girlfriend to get counselling, but he thinks she only ever went once.

"She just felt it was easier to forget about it all rather than deal with it," he said.

Despite the breakdown of the relationship, Mr Curtis believes counselling can help survivors and their partners.

"I don't regret any of it. There [are] positives that can come out of it and certainly hope, and I think because there is so many partnerships out there that one of the partners has suffered and I'll call it trauma, there can be a win/win if the couple can support one another," he said.

"If they can commit to the healing process, because it is a team effort, there's a lot that the partner can do to help the person heal and I would like all partners to think that this is a possibility."

The Royal Commission into child sexual abuse returns to Melbourne and Perth this week for more face-to-face private sessions.